This file is an exploratory analysis of the effect of climate-induced shifts in angler catch-per-trip of Gulf of Maine cod and haddock. Results are based on 100 iterations of the recreation demand model. The RDM is calibrated to 2020 fishery conditions.
Mean monthly bottom temps by decade, red line indicates decadal average. Bars represent mean temp +/- 1.96*standard dev.
Index “_i” indicates per choice occasion variable
variable mean sd
estimated_trips 312755 0.9488
n_choice_occasions 478266.5 2082.485
tot_cod_catch 587592 1805.091
tot_keep_cod 4882.56 51.4635
tot_rel_cod 582709.4 1802.771
tot_hadd_catch 1924576 3704.324
tot_keep_hadd 998495.9 1670.146
tot_rel_hadd 926080 2253.206
cod_keep_i 0.0102 1e-04
hadd_keep_i 2.0878 0.0095
cod_keep_trip 0.0156 2e-04
hadd_keep_trip 3.1926 0.0053
cod_catch_i 1.2286 0.0057
hadd_catch_i 4.0241 0.0182
cod_catch_trip 1.8788 0.0058
hadd_catch_trip 6.1536 0.0118
After calibrating the simulation model to 2020 fishery conditions, I re-ran the model under two closure scenarios: (a) bag limits for both cod and haddock set to zero, and (b) bag limits for cod only set to zero.
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CV per choice occasion
mean sd
66.1 0.4
Aggregate CV
mean sd
31611510 152193.5
Number of trips under closure
mean sd
256727.6 566.3
Number of trips under baseline fishery
mean sd
312755 0.95
Percent reduction in trips from baseline fishery
mean sd
-17.91 0.18
CV per choice occasion
mean sd
0.89 0.17
Aggregate CV
mean sd
423960.4 79141.42
Number of trips under closure
mean sd
312053 168.4
Number of trips under baseline fishery
mean sd
312755 0.95
Percent reduction in trips from baseline fishery
mean sd
-0.22 0.05
Each tab contains projected fishery outcomes based on input data from alternative copula models.
Cod and haddock keep per choice occasion:
Cod and haddock catch per choice occasion:
CV per choice occasion and number of trips:
Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):
Cod and haddock keep per choice occasion:
Cod and haddock catch per choice occasion:
CV per choice occasion and number of trips:
Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):
Cod and haddock keep per choice occasion:
Cod and haddock catch per choice occasion:
CV per choice occasion and number of trips:
Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):
Cod and haddock keep per choice occasion:
Cod and haddock catch per choice occasion:
CV per choice occasion and number of trips:
Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):
Cod and haddock keep per choice occasion:
Cod and haddock catch per choice occasion:
CV per choice occasion and number of trips:
Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):
OLS results of total monthly CV
For reference, here are the number of directed trips by mode and period (1st and 2nd half of month) in 2020 used to calibrate the model.
| mode1 | month | period | dtrip | cod_bag | cod_min | hadd_bag | hadd_min |
|---|---|---|---|---|---|---|---|
| pr | 4 | 7 | 24807 | 0 | 100 | 15 | 17 |
| fh | 5 | 9 | 1102 | 0 | 100 | 15 | 17 |
| pr | 5 | 9 | 15297 | 0 | 100 | 15 | 17 |
| fh | 5 | 10 | 5487 | 0 | 100 | 15 | 17 |
| pr | 5 | 10 | 14406 | 0 | 100 | 15 | 17 |
| fh | 6 | 11 | 5354 | 0 | 100 | 15 | 17 |
| pr | 6 | 11 | 25195 | 0 | 100 | 15 | 17 |
| fh | 6 | 12 | 1760 | 0 | 100 | 15 | 17 |
| pr | 6 | 12 | 22111 | 0 | 100 | 15 | 17 |
| fh | 7 | 13 | 3702 | 0 | 100 | 15 | 17 |
| pr | 7 | 13 | 16609 | 0 | 100 | 15 | 17 |
| fh | 7 | 14 | 13604 | 0 | 100 | 15 | 17 |
| pr | 7 | 14 | 37126 | 0 | 100 | 15 | 17 |
| fh | 8 | 15 | 5241 | 0 | 100 | 15 | 17 |
| pr | 8 | 15 | 16028 | 0 | 100 | 15 | 17 |
| fh | 8 | 16 | 6608 | 0 | 100 | 15 | 17 |
| pr | 8 | 16 | 13384 | 0 | 100 | 15 | 17 |
| fh | 9 | 17 | 5420 | 1 | 21 | 15 | 17 |
| pr | 9 | 17 | 13822 | 0 | 100 | 15 | 17 |
| fh | 9 | 18 | 5448 | 1 | 21 | 15 | 17 |
| pr | 9 | 18 | 23918 | 1 | 21 | 15 | 17 |
| fh | 10 | 19 | 294 | 0 | 100 | 15 | 17 |
| pr | 10 | 19 | 3559 | 0 | 100 | 15 | 17 |
| fh | 10 | 20 | 449 | 0 | 100 | 15 | 17 |
| pr | 11 | 21 | 32024 | 0 | 100 | 15 | 17 |
MRIP point estimates of directed trips in 2020 by bi-monthly period
Each tab below contains projected fishery outcomes at the monthly level based on input data from alternative copula models. ## {.tabset} ### Clayton (independent catch) Number of trips by month:
CV per choice occasion by month:
Cod keep per choice occasion by month:
Haddock keep per choice occasion by month:
Cod catch per choice occasion by month:
Haddock catch per choice occasion by month:
Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):
Number of trips by month:
CV per choice occasion by month:
Cod keep per choice occasion by month:
Haddock keep per choice occasion by month:
Cod catch per choice occasion by month:
Haddock catch per choice occasion by month:
Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):
Number of trips by month:
CV per choice occasion by month:
Cod keep per choice occasion by month:
Haddock keep per choice occasion by month:
Cod catch per choice occasion by month:
Haddock catch per choice occasion by month:
Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):
Number of trips by month:
CV per choice occasion by month:
Cod keep per choice occasion by month:
Haddock keep per choice occasion by month:
Cod catch per choice occasion by month:
Haddock catch per choice occasion by month:
Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):
Number of trips by month:
CV per choice occasion by month:
Cod keep per choice occasion by month:
Haddock keep per choice occasion by month:
Cod catch per choice occasion by month:
Haddock catch per choice occasion by month:
Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):
The baseline open season for cod in 2020 was Sep. 15-30 for private boat and September 7-October 8 for for-hire. Because the model time-step is bi-monthly (two periods per month: 1st half, 2nd half), I set the private open season to the 2nd half of September and the for-hire season to the 1st and 2nd half of September. Haddock was open all months except March and the first half of April (when there was no directed trips).
I specified alternative cod open seasons by month for May, June, July, August, and October. To do this, I open the 2nd half of the month for private boat mode, and I open the 1st and 2nd half of the month for the for-hire mode.
In these simulations I use independent and correlated catch-per-trip data from the clayton copula model.
Main welfare results below show the difference in total CV between baseline cod open season, and cod open season in an alternative month.
Each tab below contains projected fishery outcomes based on input data from alternative copula models. Here, I opened the cod season in different periods across the year.
Cod and haddock keep per choice occasion:
Cod and haddock catch per choice occasion:
CV per choice occasion and number of trips:
Correlation in catch and keep of cod and haddock per choice occasion (kendall’s tau-b):
Each tab contains projected fishery outcomes at the monthly level based on input data from alternative copula models. Here, I opened the cod season in different periods across the year.
The baseline open season for cod in 2020 was Sep. 15-30 for private boat and September 7-October 8 for for-hire. Because the model time-step is bi-monthly (two periods per month: 1st half, 2nd half), I set the private open season to the 2nd half of September and the for-hire season to the 1st and 2nd half of September. Haddock was open all months except March and the first half of April (when there was no directed trips).
I specified alternative cod open seasons by month for May, June, July, August, and October. To do this, I open the 2nd half of the month for private boat mode, and I open the 1st and 2nd half of the month for the for-hire mode.
In these simulations I use independent and correlated catch-per-trip data from the clayton copula model.
Number of trips by month:
CV per choice occasion by month:
Cod keep per choice occasion by month:
Haddock keep per choice occasion by month:
Cod catch per choice occasion by month:
Haddock catch per choice occasion by month:
Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):
Number of trips by month:
CV per choice occasion by month:
Cod keep per choice occasion by month:
Haddock keep per choice occasion by month:
Cod catch per choice occasion by month:
Haddock catch per choice occasion by month:
Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):
Number of trips by month:
CV per choice occasion by month:
Cod keep per choice occasion by month:
Haddock keep per choice occasion by month:
Cod catch per choice occasion by month:
Haddock catch per choice occasion by month:
Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):
Number of trips by month:
CV per choice occasion by month:
Cod keep per choice occasion by month:
Haddock keep per choice occasion by month:
Cod catch per choice occasion by month:
Haddock catch per choice occasion by month:
Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):
Number of trips by month:
CV per choice occasion by month:
Cod keep per choice occasion by month:
Haddock keep per choice occasion by month:
Cod catch per choice occasion by month:
Haddock catch per choice occasion by month:
Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):
Number of trips by month:
CV per choice occasion by month:
Cod keep per choice occasion by month:
Haddock keep per choice occasion by month:
Cod catch per choice occasion by month:
Haddock catch per choice occasion by month:
Correlation in catch of cod and haddock per choice occasion (kendall’s tau-b):